The use of filled or reinforced thermoplastics continues to attract attention for use in various applications. One technical issue faced in the art (e.g., for use in automotive or other applications) is the need to provide substantially uniform dispersions. The art has been investigating alternative approaches to the manufacture of high integrity plastics, particularly those in which a glass fiber phase is included.
Examples of efforts to improve fiber dispersions include, without limitation, Webster, U.S. Pat. No. 6,756,429 B2, “Method for Improving Fiber Dispersion and Orientation in Let-Downs of Long Fiber Reinforced Composites,” (assigned to Clariant), hereby incorporated by reference. That patent illustrates polyamide matrices incorporating modifiers.
European Patent Application No. EP1 364760A1, “Emission-Reduced Articles from Long Fiber Reinforced Polypropylene,” (assigned to Borealis), hereby incorporated by reference, teaches granules containing glass fibers coated first with one molten polypropylene, and then subsequently coated by a second polypropylene.
Published U.S. Pat. No. 7,045,202, “Long Glass Fiber Filler Reinforced Resin Material for Molding, Method for Molding Molded Article, and Molded Article Molded by the Method,” (Mazda Motor Corp.), hereby incorporated by reference, addresses a masterbatch having a polypropylene matrix and including grafted polypropylene and glass fibers. See also, Published US Patent Application US20020052440A1, “Long Glass Fiber Filler Reinforced Resin material for Molding, Injection-Molded Article Molded by Injection-Molding the Resin Material, and Method for Molding the Resin Material,” (Mazda Motor Corp.) hereby incorporated by reference.
European Patent Application No. EP 0663418 AI, “Mixture of Long Glass Fiber-Reinforced Polypropylene and Polypropylene resin and Moldings Formed Therefrom,” (Kawasaki Steel Corp.), hereby incorporated by reference, addresses a mixture that includes glass fibers coupled with grafted polypropylene.
Notwithstanding efforts to date, there remains a need for improved systems for making fiber reinforced thermoplastic articles, and particularly articles that exhibit good dispersion characteristics, such as for avoiding the formation of fiber clusters, and particularly fiber clusters that impair other manufacturing process steps (e.g., laser scoring).
There also remains a need for improved fiber-containing feedstock materials that remain substantially in tact during dry handling and processing steps in advance of melting steps.